A difference in temperature between the affected and normal extremity is one sign or symptom of reflex sympathetic dystrophy. Both patients and the literature report that the temperature can change over time. The aims of this pilot study were to investigate changes in the temperature of the extremities perceived over 1 week, and to assess whether temperature changes perceived during the previous week can be scored retrospectively by patients. The relationship with infrared outcomes was also investigated. Nine patients with reflex sympathetic dystrophy of one upper extremity were included. Using a visual analogue scale (VAS), the temperature of the extremities when completing the VAS (VAS(now)) and remembered differences in temperature in the preceding week (VAS(min) and VAS(max)) were recorded. Local infrared readouts were also obtained from both hands on entry to the study. There was no significant correlation between the VAS and infrared results. In most patients, temperature differences scored with a VAS changed considerably over time. The subjective range of differences in temperature could be scored adequately in retrospect using VAS(min) and VAS(max) scores. Further research is needed to confirm this observation and to examine the degree to which a VAS for temperature adequately represents the construct under consideration.